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Algae Repulsion Experimental Tank

Written by Aziz Dhanani

As readers recall in the the March 2008 Issue (Methods to Prevent Algae), I attempted to set up a 10 gallon tank and implemented controversial anti-algae measures to determine whether there was any merit to these measures. Some of these measure included using moss balls to soak up nutrients, noon burst lighting, and Eigera densa as a chemical agent.

While the tank held up well and remained relatively algae free for 6 months, I was rather surprised and caught off guard with the developments that ensued after 6 months. During the 6 months, the fish remained relatively healthy, the plants continued to do well, the water remained crystal clear, and what algae was mainly confined to blue green algae, which I eradicated early on and residual green spot algae which remained on a few anubias leaves and cardamine leaves.

After 6 months, chaos ensued. There were fish deaths almost weekly and I was unable to pinpoint the cause of them. This was accompanied by the growth of black brush algae. I dosed the tank with Seachem Excel and this cause the blackbrush algae to recede and eventually disappear. However, the fish deaths continued and green spot algae took the tank by storm. The whole glass was pretty much covered with green spot algae. I was at a loss to pinpoint what was causing this. I was dosing Estimative Index Dosing at the time, there was a UV sterilizer running 24/7 in the tank, the fish were not overfed, I was performing 50% weekly water changes, and trimming plants as required. Water parameters were interesting.

Why did Algae Occur? Cause and effect relationships are difficult to prove anytime you setup a tank without another control tank. Many conclusions can be drawn from the differences in the water parameters. I don't know how much those differences can really be attributed to the tank's demise.

The water parameters would suggest that at the time the tank began to experience problems, PH increased, nitrates significantly increased, GH levels more than doubled, and C02 levels may have been considerably lower. It should be noted that GH levels significantly increased as I was dosing calcium sulphate and magnesium with every 50% water change. The extremely high GH levels would suggest an overdose of calcium sulphate, but again how much of the increase in GH was responsible for the ensuing fish deaths and decline in plant growth is open for debate. What I can tell you is that after that reading, I stopped dosing calcium sulphate and magnesium and the next monthly water parameter test indicated more ideal GH levels.

One thing that I noticed is that the development of the black brush algae and green spot algae appeared to coincide with a major trim of the tank. I had performed a major trim of the Eigera densa and greatly reduced the density of floating plant mass. Later on, I completely removed all the Eigera densa as I wanted to dose the tank with Seachem Excel to eradicate the black brush algae and I knew the plant was known to be sensitive to the effects of Excel and melt, I did not want the tank water to become littered with dying Eigera densa.

By April 22 2008, I was left with one surviving otocat, and one surviving marble hatchet. I was really at a crossroads about what to do next. Given the regular occurrence of fish deaths, I was not sure if the otocat and one marble hatchet would survive. However, I did not have anywhere to put them. I decided to leave the tank running, but implemented the following remedial measures in the hopes of turning things around.

Much to my surprise, the green spot algae cleared up within a week of these measures. To date the Amano Shrimp appear healthy and I have not noticed any losses. Sadly though, the marble hatchet died after the last water parameter reading, and the otocat perished a week after that. Again, I am at a loss as to what caused their deaths.